1. Field of the Invention
The present invention relates to an autoclave that is heated by the output gas of a turbine.
2. Description of Related Art
Autoclaves are typically used to form composite parts that contain fibrous material impregnated with a thermosetting organic resin. The composite parts are formed by elevated pressures and temperatures introduced to the inner chamber of the autoclave. Heat is typically supplied to the autoclave by coils which contain a hot gas. The hot gas is conventionally produced by a gas combustion chamber.
Gas combustion chambers generate combusted gas with a temperature of approximately 3200.degree. F. The coils within the autoclave can only withstand temperatures in the range of 1300.degree. F. Temperatures above 1300.degree. F. may cause the coil material to become brittle and rupture when exposed to the pressure of the autoclave. To reduce the temperature of the output gas from the combustion chamber, conventional autoclave systems use excess air to cool the combusted gas. 300% excess air is typically required to create an output gas temperature of 1300.degree. F. Pumping excess air into the combustion chamber lowers the energy efficiency of the chamber.
The excess air is blown into the heater coils, even after the inner chamber of the autoclave has reached the desired elevated temperature. The excess air must be constantly heated to maintain the temperature within the autoclave. This constant heating of the excess air also lowers the efficiency of the overall system. It would be desirable to have a more energy efficient autoclave system.
To prevent catastrophic fires from occurring within an autoclave, it is desirable to fill the autoclave inner chamber with nitrogen. U.S. Pat. No. 5,122,318 issued to Bonet et al, discloses a process for producing nitrogen that is provided to an autoclave. The Bonet patent includes a membrane which creates nitrogen from atmospheric air. The air is pushed through the membrane by a compressor. The Bonet system also contains a second compressor which fills a holding tank with the processed nitrogen. Although effective in producing nitrogen for use in an autoclave, the Bonet process requires additional energy to run the compressors of the system. It would be desirable to have an autoclave system which can utilize the Bonet nitrogen processing plant without increasing the energy requirements of the overall system.